Controlling polymorphism during the crystallization of an atomic fluid
Controlling polymorphism during the crystallization of an atomic fluid
复制标题
DOI：
10.1103/physrevlett.98.235502
复制
发表时间：
2007-06-08
影响因子：
8.6
通讯作者：
Delhommelle, Jerome
中科院分区：
文献类型：
--
作者：
Desgranges, Caroline;Delhommelle, Jerome
我们使用分子动力学模拟来阐明 Lennard-Jones 流体结晶过程中多晶型的选择。通过在固定过冷下改变压力，我们形成稳定面心立方形式或亚稳态体心立方形式的大微晶，甚至微调微晶中稳定和亚稳态多晶型物的分数。我们证明，导致大 bcc 微晶的结晶条件位于亚稳态 bcc 多晶型物的出现范围内。我们还发现，由于 hcp 形式在 fcc 形式上交叉成核，主要的 fcc 微晶含有大量的六方密堆积形式。通过在固定压力下改变温度，我们可以防止交叉成核并形成纯的面心立方晶体。我们的结果表明，多晶型选择可能在生长步骤中发生并受到控制。
We use molecular dynamics simulations to shed light on polymorph selection during the crystallization of the Lennard-Jones fluid. By varying pressure at fixed supercooling, we form large crystallites either of the stable face centered cubic form or of the metastable body centered cubic form and even fine-tune the fractions of stable and metastable polymorphs in the crystallite. We demonstrate that the conditions of crystallization, leading to large bcc crystallites, lie within the occurrence domain of the metastable bcc polymorph. We also find that the predominantly fcc crystallites contain a notable amount of the hexagonal close packed form, due to the cross nucleation of the hcp form on the fcc form. By varying temperature at fixed pressure, we prevent cross nucleation and form pure fcc crystallites. Our results reveal that polymorph selection may take place, and be controlled, during the growth step.